In the days and weeks before the trailer dropped, dozens of people on Twitter changed their handles to some version of "GIVE TRAILER UNTITLED AVENGERS." Fans using the Twitter hashtag #MARVELVSTHEFANS made multiple videos begging the Avengers 4 directors for the trailer. Fans on Reddit shared, then deleted, moment-by-moment descriptions of what supposedly happens in the trailer, based on unofficial leaks. They pored over the social media accounts of the film's directors and stars, looking for clues to a trailer release date and a title.

Hype for a movie is one thing. But hype for a trailer? This is where we are now — and it all began more than a hundred years ago…

Footage on demand

The first-ever trailer was shown in a New York Loews cinema way back in 1913, and it wasn't even for a movie. Instead, it was a short film made to advertise the Broadway musical The Pleasure Seekers. But it was a brilliant hook: Tease entertainment seekers with a preview of another piece of entertainment they might enjoy. Naturally, the promotional films took off.

Star Wars and superhero films create the most intense demand for trailers.

Disney

Trailer hysteria isn't new, but it's certainly reached new heights, thanks to YouTube and social media, as well as the continued boom of sci-fi and superhero flicks. Studios have even managed to squeeze a little more publicity out of their trailers by offering super-short versions, often called teaser trailers.

Anton Volkov saw trailer love growing back in 2016, when he started a movie-news Twitter account and website he called Trailer Track. A wry quote from writer-director James Mangold that's pinned to the top of the site's Twitter account sums up the current trailer infatuation: "[Trailers] tend to debut a few weeks after you've reached a peak of frustration," it reads. "Marketing's like foreplay."

"This sort of level of anticipation for marketing materials, be it trailers or posters, was always there," Volkov says. "It's just becoming … more mainstream."

Constant intrigue

William Bibbiani is a film critic and co-host of Canceled Too Soon, a podcast about short-lived TV shows, and the movie podcast Critically Acclaimed. He agrees trailer madness goes back — at least decades.

"Audiences were so excited for Tim Burton's original Batman [in 1989] that many people bought tickets to another movie, just to see the trailer in a theater, and then left before the actual film began," he said.

The trailer for Star Wars: The Phantom Menace created similar buzz 20 years ago. CNET film critic Richard Trenholm calls that era, with no Facebook, Twitter or YouTube, a "veritable Stone Age" as far as viewing trailers. He notes that Steve Jobs himself described the second Phantom Menace trailer as "the biggest internet download event in history."

Three major developments in the 2000s ratcheted up the hype, Bibbiani says.

High-speed internet connections allow fans to consume trailers and marketing materials instantly and share their reactions just as quickly. The surge of successful superhero movies made "geeky blockbusters" the norm — who better than a self-proclaimed geek to dissect even the smallest movie detail? And the 24-hour online entertainment-news cycle has created a beast that's always hungry.

"Fans of these properties are being kept in a state of constant intrigue, so that new trailers — or even the conspicuous absence of new trailers — become big events, even though they are, at their core, just commercials," Bibbiani said.

Building the buzz

Marvel's extreme level of secrecy around the Avengers 4 trailer earned a lot of attention, but it's not the norm.

In 2017, extended footage from Avengers: Infinity War was shown in the summer at both San Diego Comic-Con and Disney fan gathering D23. Though that footage wasn't shared on YouTube at the time, some fans who saw it revealed what they saw, and word spread.

But until now, we saw nothing for Avengers 4 besides a release date and basic plot synopsis. "I think it's quite clear that (Marvel executives) have spotted how much buzz and conversation the very lack of content and the secrecy generates," Volkov said.

Even dedicated fans understand it's all part of Marvel's business. Alex Rodriguez, 19, started a Twitter account this year called MCU Speculation to share news and theories about the studio.

"The hype and the tension builds up more and more for each day that the trailer doesn't get released online," Rodriguez said. "This makes for a huge launch for the trailer."

Trailers still serve a purpose. Hard-core fans, the kind who wear costumes to midnight showings and buy day-one tickets well in advance, are going to see Avengers 4, preview or no preview. But a trailer can help sell a film to more general audiences.

"When a film like Avengers 4 comes in, there's always at least one writer for a site making the argument that maybe that film can get away with not releasing a single trailer," Volkov said. But he notes Marvel isn't about to leave millions on the table by not marketing the film to pull in an even larger audience.

And studio dollar-signs aside, trailers create a social experience that can be just pure fun.

"The urge to share certain experiences simultaneously is often irresistible," Bibbiani said. "And why wouldn't it be? Who doesn't love a good trailer, and who wouldn't want to talk about it with their friends? Especially if it's trending on Twitter?"

Spoilers!

There are ways to deliver the goods without driving fans to Thanos-size levels of insanity. Some studios and distributors make pre-trailer announcements. Fox and Warner Brothers have even used a Facebook and YouTube feature that counts down to the arrival of an uploaded trailer. Volkov thinks this is a smart way to build anticipation for the movie while easing fan frustration.

Movies with dramatic events that are easily spoiled have to play trailers carefully, so plot twists aren't ruined. Isn't that right, Thanos?

Marvel

When a trailer finally does drop, its actual content sometimes has little to do with the film's quality.

"We've all seen good films that weren't well served by their promotional campaigns, and we've all seen disappointing films that looked pretty good in trailer form," Bibbiani noted.

But recent films at the center of the trailer storm have unanswered questions that make their trailers even more coveted — even though the previews themselves will have to walk a fine line or risk too many spoilers.

Drawing out the wait for a trailer only makes the desire for footage more intense.

"The upcoming trailers for Avengers 4 and Star Wars: Episode IX are bound to be huge pop culture events, because both previews will … answer questions that fans have been speculating about for months," Bibbiani said. "What really happened after The Snap? And will (Episode IX director) J.J. Abrams continue down Rian Johnson's controversial path from The Last Jedi, or will he make the next Star Wars movie more like his relatively safer Episode VII?"

The trailers are unlikely to tell us, but fans will watch them intently regardless.

In 2018, anything released before a much anticipated movie, from a poster to an Instagram image, will be picked apart by viewers and entertainment sites hungry for clues. Apparently the cat in the recent poster for 2019's Captain Marvel isn't just a cat. And in September, the Russo brothers tossed out a Where's Waldo?-style challenge, inviting fans to "look hard" at what appears to be a boring black-and-white image of an almost-empty Avengers 4 set.

Drawing out the wait for a trailer only makes the desire for footage more intense. The trailer for Avengers: Infinity War wasn't released until four months after footage showed at Comic-Con and D23, which gave fans more than 100 days to moan and complain online. Even Marvel Studios co-president Louis D'Esposito tried to soothe trailer-hungry fans by tweeting that he loved the IW trailer, but wasn't ready to share it yet. When the trailer finally came out, however, fans made up for lost time. The original Infinity War trailer has been viewed more than 214 million times.

Start the countdown

Volkov says the anticipation for Avengers 4 is the biggest he's seen for any film since starting his site in 2016. After that, he ranks Avengers: Infinity War, Justice League and war movie Dunkirk as the most eagerly awaited.

"It does just come down to superhero and Star Wars films being the biggest game in town in terms of general interest and box office today," he said.

Now the Avengers: Endgame trailer has arrived, look for eager fans to start demanding the second trailer, Volkov said. And naturally, interest in Star Wars: Episode IX, due out in December 2019, will be galactically high.

But while the final film in the main Star Wars saga holds many mysteries, a trailer date might not be one of them.

"At least in the case of Episode 9, it's fairly clear and obvious that (the trailer debut) has to be at Star Wars Celebration in April," Volkov says.

You heard him, fans. Start the countdown. Only four months to go.

Now playing: Watch this: 'Star Wars: The Last Jedi' trailer debuts

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First published Dec. 4, 9 a.m. PT.Update, Dec. 4 at 9:29 p.m. PT: Adds likelihood that trailer won't be released Wednesday, as rumored, due to the funeral of George H.W. Bush.Update, Dec. 6 at 10:04 a.m. PT: Adds current prediction that trailer will come Friday morning.Update, Dec. 7 at 8:55 a.m. PT: Adds news that the Endgame trailer has finally hit.